# US 10,309,028 B2 · Method for producing surface-treated steel sheet, surface-treated steel sheet, and organic resin coated metal container

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- Number: US 10,309,028 B2
- Document ID: US10309028B2
- Status: Granted
- Kind: B2
- Application number: 15/032,956
- Filed: 2014-08-20
- Published: 2016-09-15
- Granted: 2019-06-04
- Earliest claimed: 2013-10-31
- Assignees: Toyo Kohan Co., Ltd.; Toyo Seikan Co., Ltd.
- Applicants: Toyo Kohan Co., Ltd.; Nippon Paint Surf Chemicals Co., Ltd.; Toyo Seikan Co., Ltd.
- Inventors: Kunihiro Yoshimura; Masanobu Matsubara; Marie Sasaki; Masahiko Matsukawa; Keisuke Yoshida; Wataru Kurokawa; Munemitsu Hirotsu; Mitsuhide Aihara
- Web page: https://patentgrep.com/patent/US10309028B2

## CPC

- C25D 9/10: on iron or steel
- C25D 9/08: by cathodic processes
- C25B 1/01: Products
- C25D 5/48: After-treatment of electroplated surfaces
- C25D 5/505: {of electroplated tin coatings, e.g. by melting}
- C25D 7/0614: {Strips or foils}
- C25D: PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25B: ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR (anodic or cathodic protection C23F13/00; single-crystal growth C30B)

## Abstract

Provided is a method for producing a surface-treated steel sheet including the step of forming a layer mainly composed of an oxygen compound containing Al onto a tin-plated steel sheet by conducting cathode electrolytic treatment to the tin-plated steel sheet using an electrolytic treatment solution containing Al ions and nitrate ions. For the electrolytic treatment solution, an electrolytic treatment solution not containing F ions and where the amount of nitrate ions contained is 11,500 to 25,000 ppm by weight is used.

## Claims

### Claim 1

A method for producing a surface-treated steel sheet comprising:
forming an Al oxygen compound layer which is a layer mainly composed of an oxygen compound containing Al onto a tin-plated steel sheet by conducting cathode electrolytic treatment using an electrolytic treatment solution containing an Al ion and nitrate ion to the tin-plated steel sheet,
wherein the electrolytic treatment solution does not contain F ion and where an amount of the nitrate ion contained is 15,000 to 25,000 ppm by weight,
the cathode electrolytic treatment is conducted under a condition of an amount of electricity of 0.4 C/dm2 to 2.8C/dm,
the Al oxygen compound layer has an Al amount of 2 to 11.8 mg/m2, and
a particle diameter of particles of an Al oxygen compound which form the Al oxygen compound layer is 50 nm or less.

### Claim 2 (depends on 1)

The method for producing the surface-treated steel sheet according to claim 1, wherein a value (mg/C) obtained by dividing the amount of Al contained in the Al oxygen compound layer by an amount of electricity in the cathode electrolytic treatment is 0.011 or more.

### Claim 3 (depends on 1)

The method for producing the surface-treated steel sheet according to claim 1, wherein electric conductivity of the electrolytic treatment solution is 16 to 35 mS/cm.

### Claim 4 (depends on 1)

The method for producing the surface-treated steel sheet according to claim 1, wherein a pH of the electrolytic treatment solution is 2.0 to 4.0.

### Claim 5 (depends on 1)

The surface-treated steel sheet obtained by the method according to claim 1.

### Claim 6 (depends on 5)

An organic resin coated metal container obtained by using the surface-treated steel sheet according to claim 5.

### Claim 7 (depends on 1)

The method for producing the surface-treated steel sheet according to claim 1, wherein an amount of an Al ion contained in the electrolytic treatment solution is 0.5 to 10 g/lit. in a mass concentration of Al atoms.